Windsor-based Ice Energy has a sophisticated business plan centered around a simple concept: Store electricity at night when it’s plentiful and use it during the day to cool buildings.

The company’s Ice Bear units freeze 450 gallons of water at night and the ice melts during the day to deliver cool air through buildings’ existing air-conditioning systems, reported The Denver Post. It’s cheaper and more efficient than traditional systems, according to company chief executive Frank Ramirez.

“What we really are is an energy-efficiency company,” he said.

The company, which Ramirez co-founded in 2004 with partners Gregory Tropsa and Brian Parsonnet, has received nearly $90 million in venture capital. In October it landed a $24 million investment from a group that includes TIAA-CREF.

Ice Energy’s target customers aren’t building owners looking to cut their energy bills, but utilities interested in reducing peak energy demand.

Utilities are geared up to handle maximum loads that occur for just a few hours a day during the hottest weeks of the summer. Most of the time, a big portion of their capacity sits idle. The Ice Bear diverts demand to off-peak times and, if deployed widely, would allow utilities to spend less effort preparing for peak demand, Ramirez said.

Ice Energy has a contract in excess of $100 million to supply as many as 6,000 Ice Bear units to the Southern California Public Power Authority, a collection of municipal utilities in cities including Los Angeles, Anaheim and Pasadena. It’s also in talks with other utilities, including Colorado Public Service Co. owner Xcel Energy.

Ramirez envisions Ice Bears being deployed across the U.S., but it could take decades. Utilities, he said, aren’t known for moving quickly. So far, the company has deployed 300 units.

“We’ve gotten a reasonable kick-start, but the opportunity we haven’t even begun to scratch,” he said.

Ramirez, 57, is a former Securities and Exchange Commission attorney and Bear Stearns managing partner who grew up in Pueblo and returned to Colorado with his family in 2000.